Filter dangerous html code in form submission with php

The HTML code of the PHP filter submission form may contain code that can be exploited to introduce external dangerous content. For example, sometimes the user submission form contains HTML content, but this may cause confusion in the display page layout and needs to be filtered out.

function uht($str)
{
 $farr = array(
 "/s+/", //Filter excess whitespace
 //Filter <script> and other codes that may introduce malicious content or maliciously change the display layout , if you don’t need to insert flash, etc., you can also add the filter of <object><li> "/<(/?)(script|i?frame|style|html|body|title|link|meta|?|%)( [^>]*?)>/isU", <li> "/(<[^>]*)on[a-zA-Z]+s*=([^>]*>)/ isU",//Filter the on event of javascript <li> ); <li> $tarr = array( <li> " ", <li> "＜123＞",//If you want to directly clear unsafe tags, you can leave it blank here <li> "12", <li> ); <li> $str = preg_replace( $farr,$tarr,$str); <li> return $str; <li>}</script>

php, html